/*
* Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package java.awt;
import java.awt.image.BufferedImage;
import java.util.Locale;
import sun.java2d.HeadlessGraphicsEnvironment;
import sun.java2d.SunGraphicsEnvironment;
/**
*
* The GraphicsEnvironment
class describes the collection
* of {@link GraphicsDevice} objects and {@link java.awt.Font} objects
* available to a Java(tm) application on a particular platform.
* The resources in this GraphicsEnvironment
might be local
* or on a remote machine. GraphicsDevice
objects can be
* screens, printers or image buffers and are the destination of
* {@link Graphics2D} drawing methods. Each GraphicsDevice
* has a number of {@link GraphicsConfiguration} objects associated with
* it. These objects specify the different configurations in which the
* GraphicsDevice
can be used.
* @see GraphicsDevice
* @see GraphicsConfiguration
*/
public abstract class GraphicsEnvironment {
private static GraphicsEnvironment localEnv;
/**
* The headless state of the Toolkit and GraphicsEnvironment
*/
private static Boolean headless;
/**
* The headless state assumed by default
*/
private static Boolean defaultHeadless;
/**
* This is an abstract class and cannot be instantiated directly.
* Instances must be obtained from a suitable factory or query method.
*/
protected GraphicsEnvironment() {
}
/**
* Returns the local GraphicsEnvironment
.
* @return the local GraphicsEnvironment
*/
public static synchronized GraphicsEnvironment getLocalGraphicsEnvironment() {
if (localEnv == null) {
String nm = (String) java.security.AccessController.doPrivileged
(new sun.security.action.GetPropertyAction
("java.awt.graphicsenv", null));
try {
// long t0 = System.currentTimeMillis();
localEnv =
(GraphicsEnvironment) Class.forName(nm).newInstance();
// long t1 = System.currentTimeMillis();
// System.out.println("GE creation took " + (t1-t0)+ "ms.");
if (isHeadless()) {
localEnv = new HeadlessGraphicsEnvironment(localEnv);
}
} catch (ClassNotFoundException e) {
throw new Error("Could not find class: "+nm);
} catch (InstantiationException e) {
throw new Error("Could not instantiate Graphics Environment: "
+ nm);
} catch (IllegalAccessException e) {
throw new Error ("Could not access Graphics Environment: "
+ nm);
}
}
return localEnv;
}
/**
* Tests whether or not a display, keyboard, and mouse can be
* supported in this environment. If this method returns true,
* a HeadlessException is thrown from areas of the Toolkit
* and GraphicsEnvironment that are dependent on a display,
* keyboard, or mouse.
* @return true
if this environment cannot support
* a display, keyboard, and mouse; false
* otherwise
* @see java.awt.HeadlessException
* @since 1.4
*/
public static boolean isHeadless() {
return getHeadlessProperty();
}
/**
* @return warning message if headless state is assumed by default;
* null otherwise
* @since 1.5
*/
static String getHeadlessMessage() {
if (headless == null) {
getHeadlessProperty(); // initialize the values
}
return defaultHeadless != Boolean.TRUE ? null :
"\nNo X11 DISPLAY variable was set, " +
"but this program performed an operation which requires it.";
}
/**
* @return the value of the property "java.awt.headless"
* @since 1.4
*/
private static boolean getHeadlessProperty() {
if (headless == null) {
java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction() {
public Object run() {
String nm = System.getProperty("java.awt.headless");
if (nm == null) {
/* No need to ask for DISPLAY when run in a browser */
if (System.getProperty("javaplugin.version") != null) {
headless = defaultHeadless = Boolean.FALSE;
} else {
String osName = System.getProperty("os.name");
headless = defaultHeadless =
Boolean.valueOf(("Linux".equals(osName) || "SunOS".equals(osName)) &&
(System.getenv("DISPLAY") == null));
}
} else if (nm.equals("true")) {
headless = Boolean.TRUE;
} else {
headless = Boolean.FALSE;
}
return null;
}
}
);
}
return headless.booleanValue();
}
/**
* Check for headless state and throw HeadlessException if headless
* @since 1.4
*/
static void checkHeadless() throws HeadlessException {
if (isHeadless()) {
throw new HeadlessException();
}
}
/**
* Returns whether or not a display, keyboard, and mouse can be
* supported in this graphics environment. If this returns true,
* HeadlessException
will be thrown from areas of the
* graphics environment that are dependent on a display, keyboard, or
* mouse.
* @return true
if a display, keyboard, and mouse
* can be supported in this environment; false
* otherwise
* @see java.awt.HeadlessException
* @see #isHeadless
* @since 1.4
*/
public boolean isHeadlessInstance() {
// By default (local graphics environment), simply check the
// headless property.
return getHeadlessProperty();
}
/**
* Returns an array of all of the screen GraphicsDevice
* objects.
* @return an array containing all the GraphicsDevice
* objects that represent screen devices
* @exception HeadlessException if isHeadless() returns true
* @see #isHeadless()
*/
public abstract GraphicsDevice[] getScreenDevices()
throws HeadlessException;
/**
* Returns the default screen GraphicsDevice
.
* @return the GraphicsDevice
that represents the
* default screen device
* @exception HeadlessException if isHeadless() returns true
* @see #isHeadless()
*/
public abstract GraphicsDevice getDefaultScreenDevice()
throws HeadlessException;
/**
* Returns a Graphics2D
object for rendering into the
* specified {@link BufferedImage}.
* @param img the specified BufferedImage
* @return a Graphics2D
to be used for rendering into
* the specified BufferedImage
* @throws NullPointerException if img
is null
*/
public abstract Graphics2D createGraphics(BufferedImage img);
/**
* Returns an array containing a one-point size instance of all fonts
* available in this GraphicsEnvironment
. Typical usage
* would be to allow a user to select a particular font. Then, the
* application can size the font and set various font attributes by
* calling the deriveFont
method on the choosen instance.
*
* This method provides for the application the most precise control
* over which Font
instance is used to render text.
* If a font in this GraphicsEnvironment
has multiple
* programmable variations, only one
* instance of that Font
is returned in the array, and
* other variations must be derived by the application.
*
* If a font in this environment has multiple programmable variations,
* such as Multiple-Master fonts, only one instance of that font is
* returned in the Font
array. The other variations
* must be derived by the application.
*
* @return an array of Font
objects
* @see #getAvailableFontFamilyNames
* @see java.awt.Font
* @see java.awt.Font#deriveFont
* @see java.awt.Font#getFontName
* @since 1.2
*/
public abstract Font[] getAllFonts();
/**
* Returns an array containing the names of all font families in this
* GraphicsEnvironment
localized for the default locale,
* as returned by Locale.getDefault()
.
*
* Typical usage would be for presentation to a user for selection of
* a particular family name. An application can then specify this name
* when creating a font, in conjunction with a style, such as bold or
* italic, giving the font system flexibility in choosing its own best
* match among multiple fonts in the same font family.
*
* @return an array of String
containing font family names
* localized for the default locale, or a suitable alternative
* name if no name exists for this locale.
* @see #getAllFonts
* @see java.awt.Font
* @see java.awt.Font#getFamily
* @since 1.2
*/
public abstract String[] getAvailableFontFamilyNames();
/**
* Returns an array containing the names of all font families in this
* GraphicsEnvironment
localized for the specified locale.
*
* Typical usage would be for presentation to a user for selection of
* a particular family name. An application can then specify this name
* when creating a font, in conjunction with a style, such as bold or
* italic, giving the font system flexibility in choosing its own best
* match among multiple fonts in the same font family.
*
* @param l a {@link Locale} object that represents a
* particular geographical, political, or cultural region.
* Specifying null
is equivalent to
* specifying Locale.getDefault()
.
* @return an array of String
containing font family names
* localized for the specified Locale
, or a
* suitable alternative name if no name exists for the specified locale.
* @see #getAllFonts
* @see java.awt.Font
* @see java.awt.Font#getFamily
* @since 1.2
*/
public abstract String[] getAvailableFontFamilyNames(Locale l);
/**
* Registers a created Font
in this
* GraphicsEnvironment
.
* A created font is one that was returned from calling
* {@link Font#createFont}, or derived from a created font by
* calling {@link Font#deriveFont}.
* After calling this method for such a font, it is available to
* be used in constructing new Font
s by name or family name,
* and is enumerated by {@link #getAvailableFontFamilyNames} and
* {@link #getAllFonts} within the execution context of this
* application or applet. This means applets cannot register fonts in
* a way that they are visible to other applets.
*
* Reasons that this method might not register the font and therefore
* return false
are:
*
Font
.
* Font
already
* in this GraphicsEnvironment
. For example if the name
* is that of a system font, or a logical font as described in the
* documentation of the {@link Font} class. It is implementation dependent
* whether a font may also conflict if it has the same family name
* as a system font.
* Notice that an application can supersede the registration * of an earlier created font with a new one. *
font
is successfully
* registered in this GraphicsEnvironment
.
* @throws NullPointerException if font
is null
* @since 1.6
*/
public boolean registerFont(Font font) {
if (font == null) {
throw new NullPointerException("font cannot be null.");
}
return sun.font.FontManager.registerFont(font);
}
/**
* Indicates a preference for locale-specific fonts in the mapping of
* logical fonts to physical fonts. Calling this method indicates that font
* rendering should primarily use fonts specific to the primary writing
* system (the one indicated by the default encoding and the initial
* default locale). For example, if the primary writing system is
* Japanese, then characters should be rendered using a Japanese font
* if possible, and other fonts should only be used for characters for
* which the Japanese font doesn't have glyphs.
* * The actual change in font rendering behavior resulting from a call * to this method is implementation dependent; it may have no effect at * all, or the requested behavior may already match the default behavior. * The behavior may differ between font rendering in lightweight * and peered components. Since calling this method requests a * different font, clients should expect different metrics, and may need * to recalculate window sizes and layout. Therefore this method should * be called before user interface initialisation. * @since 1.5 */ public void preferLocaleFonts() { if (!(this instanceof SunGraphicsEnvironment)) { return; } sun.font.FontManager.preferLocaleFonts(); } /** * Indicates a preference for proportional over non-proportional (e.g. * dual-spaced CJK fonts) fonts in the mapping of logical fonts to * physical fonts. If the default mapping contains fonts for which * proportional and non-proportional variants exist, then calling * this method indicates the mapping should use a proportional variant. *
* The actual change in font rendering behavior resulting from a call to * this method is implementation dependent; it may have no effect at all. * The behavior may differ between font rendering in lightweight and * peered components. Since calling this method requests a * different font, clients should expect different metrics, and may need * to recalculate window sizes and layout. Therefore this method should * be called before user interface initialisation. * @since 1.5 */ public void preferProportionalFonts() { if (!(this instanceof SunGraphicsEnvironment)) { return; } sun.font.FontManager.preferProportionalFonts(); } /** * Returns the Point where Windows should be centered. * It is recommended that centered Windows be checked to ensure they fit * within the available display area using getMaximumWindowBounds(). * @return the point where Windows should be centered * * @exception HeadlessException if isHeadless() returns true * @see #getMaximumWindowBounds * @since 1.4 */ public Point getCenterPoint() throws HeadlessException { // Default implementation: return the center of the usable bounds of the // default screen device. Rectangle usableBounds = SunGraphicsEnvironment.getUsableBounds(getDefaultScreenDevice()); return new Point((usableBounds.width / 2) + usableBounds.x, (usableBounds.height / 2) + usableBounds.y); } /** * Returns the maximum bounds for centered Windows. * These bounds account for objects in the native windowing system such as * task bars and menu bars. The returned bounds will reside on a single * display with one exception: on multi-screen systems where Windows should * be centered across all displays, this method returns the bounds of the * entire display area. *
* To get the usable bounds of a single display, use
* GraphicsConfiguration.getBounds()
and
* Toolkit.getScreenInsets()
.
* @return the maximum bounds for centered Windows
*
* @exception HeadlessException if isHeadless() returns true
* @see #getCenterPoint
* @see GraphicsConfiguration#getBounds
* @see Toolkit#getScreenInsets
* @since 1.4
*/
public Rectangle getMaximumWindowBounds() throws HeadlessException {
// Default implementation: return the usable bounds of the default screen
// device. This is correct for Microsoft Windows and non-Xinerama X11.
return SunGraphicsEnvironment.getUsableBounds(getDefaultScreenDevice());
}
}